In this case it might be piece a cake. But I can't. I only have FTP access to httpdocs directory. No ssh at all. chmod 0777 to assets/* doesn't help.
For example blog demo application should create jquery.js there. But it does n't.

To solve problem. Transfer your locally created assets folder with it's contents to server using ftp. This will ensure hosted assets folder and it's contents have appropriate owner/group id.
With everything else setup correctly look at assets error message displayed on screen. Using error example above.
Open your hosted assets folder on server, you should see two sets of folders distinguishable by uid. Open the folders with uid not 48 and search for one containing the right js files.
When files found, rename that folder to 87675fa2 based on our example. Then grant the folder and subfolders 777 permissions.
This should now work. Just repeat the process for the other assets related errors. The same solution should be applied if you get a mkdir() problem too related to assets.